Cone-beam CT for radiotherapy applications

Cho, P S; Johnson, Roger H.; Griffin, Thomas W.

doi:10.1088/0031-9155/40/11/007

Cited by 160 publications

(122 citation statements)

References 33 publications

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“…The half-fan projection data afterwards were rebinned to populate an extended full-fan sinogram representation. 35 This method works well for reconstruction of the central-slice images investigated by this study, but rapidly loses accuracy with increasing distance from the central plane. Norm-phantom calibration was also applied for the pelvic phantom in the same way, using simulated half-fan calibration-phantom projections.…”

Section: Iie Reconstruction Software and Techniquesmentioning

confidence: 76%

Monte Carlo evaluation of scatter mitigation strategies in cone‐beam CT

Lazos

Williamson

2010

Medical Physics

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Purpose: To investigate the efficacy of two widely used scatter mitigation methods: antiscatter grids ͑ASGs͒ and beam modulating with bowtie filters ͑BTFs͒, in combination with subtractive scatter correction or zeroth order normalization phantom calibration, for improving image noise, contrast, contrast-to-noise ratio ͑CNR͒, and image uniformity for on-board cone-beam CT ͑CBCT͒ imaging systems used for image-guided radiation therapy. Methods: PTRAN Monte Carlo CBCT x-ray projections of head and pelvic phantoms were calculated for combinations of beam-modulation and scatter rejection methods and images were reconstructed by in-house developed software. In addition, a simple one-dimensional analytic model was developed to predict scatter-to-primary ratio ͑SPR͒ and CNR as a function of cylindrical phantom thickness, ASG transmission, and beam modulation with bow-tie filters. Results: ASGs were found to have slightly negative or no effect on head phantom image CNR and to modestly improve CNR ͑10%-20%͒ in pelvic phantom images. However, scatter subtraction and norm-phantom calibration perform better when applied on data acquired with ASGs. Scatter subtraction improves CT number accuracy, but increases noise, and in high SPR/low primary-photon transmission scenarios can dramatically reduce CNR and introduce streaking artifacts. The BTF is found to reduce SPR and image noise, resulting in a better trade-off between CNR and imaging dose, but introduces a circular band artifact. Conclusions: Our study shows that ASGs have a modest positive impact in pelvic scans and negative in head scans, scatter subtraction improves the HU accuracy but reduces CNR, while BTF has a clearly positive effect.

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Section: Iie Reconstruction Software and Techniquesmentioning

confidence: 76%

Monte Carlo evaluation of scatter mitigation strategies in cone‐beam CT

Lazos

Williamson

2010

Medical Physics

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“…Since that time, several CBCT systems have been developed for use both in the interventional suite and for general applications in CT angiography. 2,3 Exploration of CBCT technologies for use in radiation therapy guidance began in 1992, 4,5 followed by integration of the first CBCT imaging system into the gantry of a linear accelerator in 1999. 6 The first CBCT system became commercially available for dentomaxillofacial imaging in 2001 (NewTom QR DVT 9000; Quantitative Radiology, Verona, Italy).…”

Section: Onebeam Ct (Cbct) Is An Advancement In Ct Imagingmentioning

confidence: 99%

Conebeam CT of the Head and Neck, Part 2: Clinical Applications

Miracle¹,

Mukherji²

2009

AJNR Am J Neuroradiol

301

207

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SUMMARY: Conebeam x-ray CT (CBCT) is being increasingly used for point-of-service head and neck and dentomaxillofacial imaging. This technique provides relatively high isotropic spatial resolution of osseous structures with a reduced radiation dose compared with conventional CT scans. In this second installment in a 2-part review, the clinical applications in the dentomaxillofacial and head and neck regions will be explored, with particular emphasis on diagnostic imaging of the sinuses, temporal bone, and craniofacial structures. Several controversies surrounding the emergence of CBCT technology will also be addressed. C onebeam CT (CBCT) is an advancement in CT imagingthat has begun to emerge as a potentially low-dose crosssectional technique for visualizing bony structures in the head and neck. The physical principles, image quality parameters, and technical limitations relevant to CBCT imaging were discussed in Part 1 of this 2-part series. The second part presented here will highlight the evidence related to CBCT applications in head and neck as well as dentomaxillofacial imaging. Controversial aspects of this technology will also be addressed, including limitations in image quality and its often officebased operational model.CBCT was first adapted for potential clinical use in 1982 at the Mayo Clinic Biodynamics Research Laboratory. 1 Initial interest focused primarily on applications in angiography in which soft-tissue resolution could be sacrificed in favor of high temporal and spatial-resolving capabilities. Since that time, several CBCT systems have been developed for use both in the interventional suite and for general applications in CT angiography. 2,3 Exploration of CBCT technologies for use in radiation therapy guidance began in 1992, 4,5 followed by integration of the first CBCT imaging system into the gantry of a linear accelerator in 1999. 6 The first CBCT system became commercially available for dentomaxillofacial imaging in 2001 (NewTom QR DVT 9000; Quantitative Radiology, Verona, Italy). Comparatively low dosing requirements and a relatively compact design have also led to intense interest in surgical planning and intraoperative CBCT applications, particularly in the head and neck but also in spinal, thoracic, abdominal, and orthopedic procedures. [7][8][9][10][11] Diagnostic applications in CT mammography and head and neck imaging are also under evaluation. 12-14 The technical and clinical considerations pertaining to CBCT imaging in many of these applications have been the subjects of several recent reviews. [15][16][17][18][19] The recent review by Dörfler et al 16 of the neurointerventional applications of CBCT is of particular interest to the field of neuroradiology.The discussion below will focus on the diagnostic and treatment-planning applications of CBCT in dentomaxillofacial and head and neck imaging. Commercially available CBCT systems for dentomaxillofacial imaging include the CB MercuRay and CB Throne (Hitachi Medical, Kashiwi-shi, Chiba-ken, Japan), 3D Accuitomo products (J. Mor...

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“…In 2001, the first dental CBCT radiograph had became commercially accessible for the dentomaxilofacial imaging [5]. This was the beginning for the commercialized used of the CBCT.…”

Section: Int J Adv Res 5(2) 1787-1793mentioning

confidence: 99%